The present invention relates to a pneumatic clutch apparatus in which a pressure plate is adapted to be forced by a pneumatic actuator.
Generally in a cluth for an automobile and others, a friction facing of a clutch disc is designed to be pressed by a pressure plate against a flywheel. Further, in the conventional clutch, a clutch spring or springs are provided to force the pressure plate toward the friction facing, and a release mechanism is provided to release an elastic force of the springs from the pressure plate.
However, in the above structure, when the friction facing is worn, the pressing force of the springs decreases. Therefore, it is impossible to use the facing when it is worn to the large extent, which reduces a durability. Further, each time the facing and the release mechanism are worn to some extent, each part requires adjustment.
Furthermore, there are such disadvantages as a large number of parts and a large force being required to depress a clutch pedal.
In order to solve the above disadvantages, the applicant has already disclosed a pneumatic clutch in U.S. Patent application Ser. No. 381,758, Pat. No. 4,479,570 (German Pat. Appln. P 32 19 768.3). This pneumatic clutch is provided with a pneumatic atcuator for forcing a pressure plate. However, the conventional pneumatic clutch has following problems in connection with a rotary joint. Namely, the conventional rotary joint is unstable in the installation condition. Further, passages for supplying lubricating oil into the rotary joint are complicated. Still further, there is a possibility that the lubricating oil may leak into an air passage in the rotary joint. Furthermore, the assembly operation is laborious.
Accordingly, it is an object of the invention to provided an pneumatic clutch apparatus, in which a rotary joint is improved so as to overcome the above-noted disadvantages.
Other and further objects, features and advantages of the invention will appear more fully from the following description of the preferred embodiments of the invention.